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Stairs 9: Answers on Building Stairs

Deck stairs on uneven ground
Pine on stair treads
Refinishing Skirt Boards
Bottom of stringers on concrete
2x12s for stair treads
Attaching Hardwood to Existing Stairs
One Less Run Than Risers
When to Use a Landing
Nail or Screw Size for Stairs
Securing the Bottom of a Stair Stringer to Pavement
Distance Between Newel Posts
Spacing Spindles In A Stair Railing
Replacing a Cement Stair Landing
Cutting a Stair Stringer for Existing Stairs
Stair Tread Thickness Does Not Affect Total Rise
Allowing For Stair Tread Thickness
Protecting Outside Stairs
Standard Height of One Story of a House
Angle of the Stair Stringers
Height Variations in Stairs
Adjusting Stairs for an Uneven Floor
Attaching Stair Treads to Stair Stringers
Fitting Stair Treads Into Stair Stringers
Glass Pane Railings
Replacing or Tiling Over Risers
Trimming Stair Walls
Different Length Risers
Stair Winders
Straight Cuts on Stringers
Riser On Top Of or Under Tread
Attaching Stringer to Floor Joist
Unusual Rise/Run Sizes
How to Build Deck Stairs
Attaching Top Rail to Newel Posts
How to Stabilize Stringers
Splicing Long Stringers
Veneering an Existing Skirt Board
Standard Size of Stringer
Width of stairs

Question about deck stairs on uneven ground:

I am building new deck stairs for our backyard wood deck. I am planning 4 steps, 8 feet across with a total run of about 42 inches. The total rise on one side is 29 1/2 inches and the other side is 33 1/2 inches. I plan the step rise to be about 7 inches and the run about 10 1/2 inches. I am planning on using 6 stringers across the 8 foot width of the deck stairs. How do I cut the bottom of the deck stair stringers so the steps stay level to make up for the unevenness of the ground.


There is a difference in elevation in your deck stairs of 4" from one end of the deck stairs to the other. Let's split that and fiqure out the rise and run at the center of the deck stairs. You need 5 rises of 6.3" and 4 runs of 10.5". Here is a drawing to explain what I'm doing:

Diagram of deck stairs with stringers down onto ground sloped perpendicular to the line of the stringers with measurements.

Notice the deck stair stringers are on center, the overhang on each end is 1 1/2" plus half the thickness of stringer - 3/4" = 2 1/4". I broke the heights down for each deck stair stringer and the distances for each stringer as follows: Stringer 1 bottom rise is 4.3"; 2 is 5.1"; 3 is 5.9"; 4 is 6.7"; 5 is 7.5" and 6 is 8.3". Your pattern deck stair stringer will be laid out for the above run and rise - 10 1/2 and 6 3/8" respectively. The rise I gave you is before the thickness of the tread is taken off. I suspect you will go with a 1 1/2" tread but you may go with 1" as well (5/4"). So don't forget to cut the thickness of the tread off the bottom of each deck stair stringer as per a usual stringer. When you layout the pattern deck stair stringer go ahead and cut off the thickness of the tread. Then after marking the other 5 deck stair stringers we will cut off an additional .4" (7/16") and call it #3. So when you come to deck stair stringer #1 you cut off 2" from the pattern deck stair stringer. Stringer number 6 has 2" added on to the bottom of the pattern. Deck stair stringer 2 has 1.2" cut off; #4 has .4" added on and #5 has 1.2" added on. I suggest a mud sill of treated 2x10 to nail the deck stair stringers to on the bottom, if the ground they rest on will be dirt or grass, etc. keep the top of the mud sill flush with the top of the dirt, etc. if this is where you originally measured the total rise of the deck stairs. If the bottom is concrete like a side walk or whatever, lay the mud sill on top of the concrete and cut off an additional 1 1/2" off the bottom of each deck stair stringer to compensate.

Question about pine on stair treads:

Is pine okay for stair treads or is it too soft a wood?


Pine is okay for stair treads as long as you finish it with a urethane or Varathane® finish, which is hard and stands up well for floors. If you are going to use 3/4" pine though, you should have plywood as a backing and make sure it is dry. Stair treads should have a nosing about 1" long and usually 1" thick. If you use 1 1/2" pine you can fasten it right on the stair stringers without plywood first. Again, it's very important to use dry material.

Question about refinishing skirt boards:

I just had new floors installed, including some stairs. Now I want to replace the skirt boards with oak to match the stairs. Treads and risers were cut and installed to match the old fir skirt boards, and oak is thicker dimension. Where do I start?


You actually should cover the skirt board before the stair treads and risers are installed for easier installation. However, now that the stair treads and risers are on, I would use thin veneer to cover the skirt, like 1/8" to 1/4" oak in 4'x8' sheets. Make a pattern from cardboard. Cut these strips a bit wider than the skirt board to allow for scribing against the stair tread and riser for a tight fit. Once you are happy with the fit, trim the veneer off flush with the top of the skirt board and finish it with a piece of oak running the length of the skirt acting as a cap to cover the end grain of the veneer and top edge of the old skirt.

Question about bottom of stringers on concrete:

The bottoms of my stair stringers are resting directly on concrete. How can I maintain some sort of dry spacing so they don't rot out like the old ones did?


If the stair stringers aren't treated, put a piece of asphalt shingle between them and the concrete. Concrete and wood don't react well together in a damp environment, as you've seen. This should keep the wood dry. You should be able to find discarded pieces of shingle at a local construction site.

Question about 2x12s for stair treads:

I used 2x12 non-pressure treated boards for the stair treads. A couple of carpenters told me the stair treads should be ripped into two 5 3/4" stair treads to avoid splitting and cupping of the stairs in a couple of years. Any advice on this?


They're right, the 2x12s will probably split in a few years. I usually just make my stair treads out of 2x6s. If it's a big job to remove them, I would leave it until they warp or split. If the boards will be painted, don't worry about it; if they split just fill up the split with a latex or silicone caulking, repaint and no one will know the difference. If you decide to take them off, which I don't advise, be sure to leave a 3/16" air space between the two boards. You might just split them the wrong way by removing them.

Question about attaching hardwood to existing stairs:

How should new hardwood be attached to an existing stair case?


When installing hardwood or finished wood over an existing stair, be aware of any change to the height of the top and bottom stair risers. Be sure to allow for this if the hardwood isn't going over the top and bottom floors, as well. Remove any existing hardwood or carpet down to the plywood stair treads. If there is any nosing or overhang on the plywood stair treads, remove them by cutting the nosing flush with the riser. Re-nail or screw your plywood stair treads securely. Also check your stair stringers to be sure they are in good shape. It is easier to replace or repair stair stringers now rather than later.

If you are putting in finished risers as well, put them in before the stair treads. Make the top of the riser flush with the upper plywood stair tread to help support the nosing. That is, the stair tread will be supported by the riser below it. You will have to purchase a nosing to match your stair treads, in tongue and groove and thickness. You can also buy pre-fab stair treads with nosing attached.

First, cut the nosing to length for the particular stair tread. Place it temporarily in position on the stair tread and scribe a line at the back of the nosing on the existing stair tread. Remove this nosing and calculate the width of piece you need at the back of the stair tread (it usually needs to be ripped). Then install the pieces from the back (tight against the riser) towards the nosing. Notice that the nosing has the same matched groove as the flooring's tongue, so orient the flooring strips so the tongue is towards the nosing. For a wide stair tread you probably will need the nosing plus 3 pieces of hardwood plus the ripping of about 1" or so, depending on the width of the strips. These strips are nailed in as is the floor, through the tongue. The back strip or two, can be face nailed. Use no glue on the strips. Fit these pieces snug to the sides of the stairs, no expansion joints here. Then when all the strips are installed the nosing can be slid in. Use glue here to hold the nosing securely and in the tongue and groove of the nosing and its matching flooring strip. Nail through the face of the nosing with some finish nails every 6" and set them below the surface to be filled. If the flooring is pre-finished and the nosing is not, sand the nosing down before installation so it is flush with the flooring.

Apply a urethane finish over the nosing and new stair treads, after a light sanding.

Question about one less run than risers:

Why does your Stair Calculator always give one less run than the number of risers?


A carpenter usually never builds his first step even with the top floor, he drops the first step down one riser. This riser is the one that puts the number of runs one less than the risers, but it still has to be in the calculation of the total rise. The only time I ever build the top step level with the floor is when I build a set of stairs outside of a patio door, when an older couple may trip over the sill on their way down to the first step. In this case the number of risers equals the runs.

Question about when to use a landing:

Should I add a stair landing in the middle of a 10' rise or use stronger wood for the stair stringer?


On a 10' rise a 2x12 stair stringer is good. I would put a post under it in the middle just to take the bounce out. The maximum rise between stair landings (according to the Building Code) is 12', but a stair landing in the middle of a 10' rise would certainly be a good idea. You could change direction as well, if desired. Put in two stair stringers for 3' wide stair treads 1 1/2" thick, with the stair treads overlapping the stair stringer 4" to 6". Wider than 3' use more stair stringers, at about 2' centers.

Question about nail or screw size for stairs:

What size nails or screws would you suggest using for nailing/screwing the risers if I'm using 1/2" plywood for the risers?


Use 1 1/2" finish nails and glue for the face of the riser to the stair stringer and use #6x1 1/2" screws and glue from the back of the riser to help support the stair tread.

Question about securing the bottom of a stair stringer to pavement:

How do I secure the bottom of the stair stringer to the paving slab?


Depending how long the stairs are and how the stairs are supported at the top and in the middle, the bottom of the stair stringer doesn't have to be supported. It will just sit down on the pavement by itself. Usually when I want to nail the bottom of the stair stringer secure, I either notch out the stair stringer bottoms to fit over a 2x4 nailed to a stair landing or nail the 2x4 between the two stair stringers. The 2x4 is then nailed or screwed into the stair landing or wood or concrete pad, before the bottom stair tread is installed. If you want to do this, nail a couple of concrete nails into the paving through the 2x4. I hope I understand that the paving you are refering to is asphalt paving.

Question about distance between newel posts:

What is the recommended distance between newels for a balcony?


There is nothing hard and fast on this. It depends, of course, on the size of top and bottom rails. Personally, I try to limit the distance to around 6' between newel posts and have gone as far as 8' on a curve. Over 8', put in a middle post for sure. I'm talking here about a 2 1/2" x 2 1/4" nominal oak or hemlock top rail.

Question about spacing spindles in a stair railing:

How do I determine an equal size to cut each spacing block when figuring a maximum 4" between spindles? I want a 4" maximum spacer after the first post and before the last post, but no matter what I do I end up either short or long at the end!.


I think what is happening in your case is you are measuring the slope of the stair railing and the horizontal distance between spindles, which are two different measurements.

To clarify the building code: It is not just 4" between spindles that is necessary, but that a ball of 4" in diameter cannot pass through the spindles. (The 4" ball refers to a baby's head). If the spindles have deep turnings on them, you can see what the code is referring to.

What I do is instead of using 4" between posts is figure on 5" centers of spindles. This gives 3 1/2" between. Usually two spindles will work per stair tread. You not only have to have the spindles evenly spaced but they should be the same placement on each stair tread. This requires a bit of fiddling. Don't be too set on having the first and last spindle the same as your spacing between the spindles themselves. What is important is that the distance between the first and last spindle is the same and that it prevents a 4" ball from passing through the space. Rather than start at the ends, work from the center of the section each way. On different length sections use the same spacing between spindles, but differ the spacing between the first and last spindle and the newel post or wall. Another tip, if the spacing at the ends of the section are too close or to distant, change your center point on a space instead of a spindle or vice versa. You will notice that figuring on 5" centers will be easier than figuring on a space. Rather than dry fitting everything, try laying out the location of the spindles on the stair railing with painter's masking tape to mark on. Once the centers are determined, lay out the position of a few spindles to calculate your spacer blocks. The first and last will probably be different than the typical blocks between spindles. Lay out all the sections before cutting anything to see if the spacing works for all of them. A slight adjustment may be needed to satisfy all the sections and to maintain your selected spacing between spindles.

Question about replacing a cement stair landing:

I took the old cement stair landing out from under the front stairs because it was not level. How would you go about replacing the old stair landing with a new one?


Here are three choices:

  1. Replace the stair landing with cement pads bought from a building supply store and bed them down on compacted sand.
  2. Pre-fab your own stair landing from concrete by making a form of 2x4's on edge on a sheet of plywood and placing a grid of re-bar inside and mixing up pre-mixed concrete mix in a wheel barrow. Let it cure for at least a week then slip it in under the stairs. Don't make it too big or you won't be able to lift it.
  3. Form and pour the stair landing in place. Use 2x4 forms again. Hold up the stairz with bricks or suitable rocks so they are level and pour the concrete up to the bottom of the stair stringers.
Question about cutting a stair stringer for existing stairs:

I've got a nice stair case but it needs support stair stringers. How do I cut the stair stringers?


This is quite a difficult task, to say the least.

With the stair treads on, the finish stair stringer will be scribed tight to the risers and stair treads including around the nosing. This is what I would do, if removing the stair treads is out of the question:

  • Don't use the finish board to start, use a heavy piece of cardboard or I prefer a piece of 1/8" or 1/4" plywood to use as a template. Rip the plywood 10 1/4" wide or to match your finish stair stringer board's width.
  • Lay the template down on the stair treads, up against the wall on the angle it will be installed in, with the corner of the end of the board just resting on the lower floor. Fasten this board to the wall or have someone hold it steady.
  • Lay a framing square on top of each stair tread with the tongue up and the body down on the stair tread. Now push the square so the tongue touches the nosing and is up against your template. Scribe the bottom of the square out along its length and along the tongue on the nosing side up above the stair tread. Start at the bottom stair working your way up the stair stringer. You will see that the stair tread and nosing lines are intersecting.
  • Now remove this board and lay it down on the flat. Measure how far the nosing sticks out past the riser. Scribe a line inside the nosing line, on the board, by this much. Measure how thick the stair tread is at the nosing and scribe a line on your board accordingly. Do this for every step.
  • Cut out below these lines to match the contour of the stairs. Now place this template in position and see how it fits. This is where a set of scribers will help. If you don't have scribers use a compass. Fasten the template on the wall, again, and set the scribers to the largest gap showing and scribe around the horizontal lines if needed or along the vertical lines if needed or both. Remember that the template needs to move the way you scribe it so allow for that. Hopefully the amount of the scribe needed will be maybe 1/4" at the most and this 'movement' will not matter. When the template fits okay, notice the lower end where it meets the floor. At this point the board should go along the floor then up 90 degrees to meet the top slope, ie. the top slope should not come down to a point on the floor. Let the top end run wild (don't cut it off), until later.
  • Once you are happy with the fit of the template on the stairs, lay it carefully on the finish stair stringer and scribe it. Cut this out carefully. Lay it in position and carefully scribe it to remove any deficiencies. When you are happy with the fit, cut off the top end where you want it. Like the bottom end the top should meet the top floor at a 90, as well. Now that you have installed the stair stringer to the wall, you have some options: If the steps are painted and the stair stringer is painted, to fill in any imperfections in the fit, just apply some paintable latex cauking around the contours of the stairs against the stair stringer. If you can't possibly get the fit any better, but you are not happy with the fit and the stair treads are carpet or hardwood and the stair stringer is hardwood, you could cover the gap with a small molding or a caulking to match the hardwood (if stair and stair stringer are both hardwood). Finish off the top of the stair stringer with a cap or cove molding.
Question about stair tread thickness does not affect total rise:

Does the thickness of the stair tread change the total rise?


The thickness of each stair tread does not affect the total rise whatsoever. When the stair stringer is laid out the thickness of the stair tread is taken off the bottom of the stair stringer and added on at the top when you install the stair stringer, so it cancels itself out. When you put on the stair tread, the rise remains the same, since you add the thickness of the stair tread on the top of the riser and subtract the thickness on the bottom of the same riser. These two also cancel each other out.

When calculating the rise for a stair stringer do not figure in the stair tread thickness. See article Stairs 2: How to Cut a Stair Stringer for more information.

Question about allowing for stair tread thickness:

If I cut 16 runs at 7 1/2", wouldn't my very first step be 9"?


If your stair treads are made from 2x4's or 2x6's, they are 1 1/2" thick. Cut 1 1/2" (or whatever stair tread thickness you have) off the bottom of the stair stringer and install the top step of the stair stringer down 9" (in your case) from the finished floor. When you put the stair treads on, you are adding 1 1/2" to the bottom rise of 5" which equals 7 1/2" and subtracting 1 1/2" to the top rise of 9" which equals 7 1/2", making all the rises the same height. See my article Stairs 2: How to Cut a Stair Stringer for more information.

Question about protecting outside stairs:

The inspector said I have to protect my outside stair stringers from the concrete on the outside stair landing. What does he mean?


If the stair stringers are not of pressure treated wood, they must be protected from the concrete either with a Copper Napthenate preservative or with a layer of mineral felt roofing or with sill gasket, a styrofoam type of material made to go under 2x4's and 2x6's. My choice is the sill gasket, available at building supply stores.

Wood on concrete just rots because it never dries out and bugs love damp wood.

Question about standard height of one story of a house:

What are the measurements of one story or the total rise of a one story staircase?


The total rise for one story in a house is 106 3/4". Based on 92 1/4" studs, 3 plates, 2x10 joists and 5/8" thick sub-floor. This equals 14 risers at 7 5/8".

Question about angle of the stair stringers:

How do we get the correct angles to cut the stair stringers and stair railing posts?


When laying out or cutting the stair stringers, don't think of angles. Your steel square, set to the rise and run, gives you the correct angle automatically. This is covered in Stairs 4: Building Stair Stringers, section The Layout.

For the angle on top of the stair railing post, lay a 2x4 down the stairs, resting on the nosing of each stair tread and touching the stair railing post. Scribe the vertical angle of the post onto the 2x4. Then set your miter saw or circular saw to that angle or just cut the 2x4 along the line you just scribed and use it to set the angle of the saw. Cut each stair railing post with this same angle. For the ends of the stair railing itself, use this same angle. Just be sure when cutting the ends of the stair railing that you cut on the same side of the board so the ends are parallel to each other. In other words, don't flip the stair railing board over between the end cuts.

Question about height variations in stairs:

One stair in my basement stairs is shorter than the rest by about 1/4". I'm thinking of two solutions, but wanted to see what you say first:

  1. I can put in a stair landing at the faulty stair, but I think this may create more problems with stair rise, etc.
  2. Pad all the stairs with, say, 7/16" plywood except the short stair which I would only pad with 3/16". I think this sounds right but have a bad feeling it won't work.

What do you think?


Interesting that you picked up on a 1/4" flaw in height between two stair risers. Actually, the National Building Code allows a tolerance of 1/4" in height between stair landings in a staircase. I was told by a building inspector once to add a step because I was 1/8" over the maximum rise on a two step set of stairs from a garage to a basement. I didn't! Another inspector gave me the final approval without even mentioning the steps.

If you are really unhappy with that riser, try to correct the riser itself. If there is carpet on the stairs, peel off the carpet over that stair tread and either plane it off 1/8" to 1/4" or remove the stair tread and cut down the riser a bit on the stair stringer itself.

When you start adding 7/16" to the other stair treads and 3/16" to the high stair tread this does create problems. Unless you add 7/16" to the bottom floor and the top floor as well, it will throw your bottom and top risers out. You have to look at the whole picture.

Your stair landing solution is okay, but it will not change the risers. A stair landing is just a long stair tread in a set of stairs. The rise is or should be the same between a stair landing and each adjacent stair. However, to change the stair case by adding the stair landing is a lot of work. I would just fix the riser itself on the stair stair stringer.

This situation is where I can stress the importance of using stair gauges when laying out a stair stringer to ensure that every rise and run is exactly the same.

Whenever you contemplate changing the height of risers, don't forget the top and bottom floors.

Note: After this answer was e-mailed to the questioner, he discovered that the difference in the height of each stair varied by as much as 2". Dave's response to this new information was that it was probably best to tear out the old stairs and build new ones.

Question about adjusting stairs for an uneven floor:

The level of the concrete in my basement floor is off about an inch between where the ends of the stair stringers will be. This means the stair stringer height will be different. How should I fit and trim these two stair stringers?


If you can't fix the floor to make it more level for future covering, go ahead and trim the last riser and the stair stringer. Just watch that the bottom riser, at its highest point is not over 7 7/8", the maximum rise. Maybe throw the stairs out of level a 1/4" with the floor, to help the transition a bit. Keep it level on the top - the main floor.

I've seen the upper floor out 3/4" in 3' before. You do what you have to do. If it can't be rectified easily, give a bit, so it is not as noticeable.

Question about attaching stair treads to stair stringers:

With an open riser stair, how do you connect the stair treads to the stair stringer?


On outside stairs I use 3" galvanized casing nails or 3" screws to hold the stair treads of 1" to 1 1/2" stock down, on inside use nails or screws and glue.

Question about fitting stair treads into stair stringers:

Some stairs are made by cutting a grove in the stair stringers for the stair threads to fit into. Is this done with a router? If so, what kind of jig does it require?


Yes, some treads are housed in the stringer. A router, Skil saw, radial arm, etc. can be used to do this. For a router, a custom jig, such as a piece of plywood with a hole in it, is used. This jig would guide the router, fitted with a guide bushing, around the hole that would be the same dimension as the groove or dado plus the thickness of the bushing edge to the router bit.

I prefer to cut out the stringers completely for a couple of reasons: the stringer is not weekened and especially on outside work, the water can run away better, rather than get trapped in the dado and cause problems with rotting. I live on the west coast with lots of liquid sunshine (rain).

With inside work, on a fancy staircase, I cut out the stringers for good support, then nail the exposed stringer on the outside of the support stringer; then assemble the two together on the wall. The extra cost of material usually offsets the cost of labour.

Question about glass pane railings:

What would be the best railing-baluster combination for a glass pane?


On the handrail for glass, the least amount of wood necessary to support it, the better. Use a 2x6 cap with 3/4" rippings to act as stops for the glass panel. Use 4x4 for vertical supports placed no more than 6' apart. It is important to install safety glass panels in a handrail. Talk to your glass supplier before making the handrail - they have precut widths of hardened glass that are cheaper than getting them cut to your sizes. A tee rail on the bottom is good to support the weight of the glass. This is a 2x4 on the flat above a 2x4 on edge in the center. Glass stops are installed on all four sides of the glass, inside and out.

Question about replacing or tiling over risers:

I want to replace my existing painted wood risers with slate or some durable tile. Is this possible and if so, how do I remove them to replace them or should I tile right over the existing riser?


If the nosing or overhang on the treads extends out enough from the riser, I would just sand the gloss off the existing risers and use them for backing to hold the tile on. There's no minimum overhang required in a staircase, but the overhang should at least cover the thickness of the tile. A nosing looks better, in my opinion, if it overhangs the riser. Conventionally the nosing is 1". In your case, if it still overhangs by 1/2" or so, go for it.

Question about trimming stair walls:

I'm going to be installing yellow pine over the stairs inside my house. They are between two walls and I would like to put trim boards along the walls on both sides, down the stairs. How is this typically done?


I take it you're covering an existing set of stairs with the pine. In this case the trim board is put in before the risers and treads. If you are building the stairs from scratch, nail this board to the stringers before attaching the stringers to the walls. If the stairs are in place you have to scribe each tread and riser and cut them out. You don't have to be too accurate here because the tread and riser will butt up against this piece hiding any gaps up to their thicknesses. When installing the treads and risers of pine make them tight to the trim board. Wood has very little expansion on its end grain. Before installing hardwoods or finishes allow them to lay in the house for 48 hours to acclimatize to their new environment. Professional installers actually have a moisture meter to measure the amount of moisture in the subfloor as well as the hardwood.

Question about different length risers:

I have a 21" plumb from my deck to the concrete below. My problem is that the concrete is not even, it slopes away from the house. I'd like to use two risers (2x10) and then bracket two steps between them. How do I measure the distance of the risers, as they will be different?


The measurement of the total rise is from the deck level to the point where the last tread will sit. If the ground is sloped, don't measure straight down below the deck; measure out where the bottom step will sit. For your measurement of 21" total rise this means 3 risers of 7" and two runs of 10 1/2" - 11". So your bottom step will sit either 21" or 22" out from the face of the deck. Measure down at this point level with the deck surface and adjust your calculations slightly for the total rise. Now when you cut your stringers allow for the slope of the concrete and scribe this slope on the bottom of the stringers.

It just dawned on me that the slope you are talking about could be going across the stairs instead of what I presumed, sloping away from the deck. If you are talking about the slope going across the stairs, ie. if one side of the stairs is higher than the other, this requires a measurement on either side where the stringers will sit. Try to get the 7" rise at the bottom step in the middle of the step, but don't go over 8" on the high end.

Question about stair winders:

How do you build winder stairs to save space?


Personally I hate winders, but if you don't have room for a landing, here you go. Here is what the Canadian Building Code says on this subject:


Where a stair must turn: the safest method of incorporating the turn is to use a landing, Inside a dwelling unit however, where occupants are familiar with their environment, winders are an acceptable method of reducing the amount of floor area devoted to the stair and have been shown to be no more hazardous than a straight run of steps. Close-up of stair case winders with angles. Nevertheless, care is required to ensure that winders are as safe as possible. Experience has shown that 30 degrees winders are the best compromise and require the least change in the natural gait of the stair user. The Code therefore permits only this angle. Although it is normal Code practice to specify upper and lower limits in this case it is necessary to limit the winders to one specific angle with no tolerance above or below this angle other than normal construction tolerances. One result of this requirement is that winder-type turns in stairs are limited to 30 degrees (one winder), 60 degrees (two winders), or 90 degrees (three winders). It should be noted that winders are not permitted to converge to a point.

Copyright is owned by the Queen's Printer.

As you can see the Code is in metric, however I'm not. Notice the line of arrows marked 251, 259 and 251 around the winders. This is called the line of travel and should be the same run as the rest of the set of stairs.

This line of travel is about 18" from the inside of the steps. This is what causes the winders to trip people if it is too narrow here.

The pointed part of the winder on the inside should be no less than 6" wide, in other words, they cannot come to a point. For this to work, the normal line of the landing comes down the stairs almost a run and the upper set of stairs goes above the normal line of the landing by the same amount. So, instead of gaining two steps, you lose two, which is about the same for a landing anyway.

Also you mentioned wanting to put in four winders. The code says three is the max with 30 degrees each making a turn of 90 degrees. Lay your particular situation out to scale on a piece of paper to see actually how much you gain and if it is worth the hassel. I learned this from experience when I was renovating for my daughter. I laid the stair opening out expecting to gain two risers and three runs. Wrong! It doesn't work that way. I ended up cutting the opening bigger and putting in a landing.

To see some photos from a member on a set of winders he built click here.

Question about straight cuts on stringers:

I'm pretty good with tools, but I'm concerned with getting straight cuts on the step stringers with my circular saw. Are there any tricks or helpful hints on making straight cuts?


The one thing I do when cutting with a circular saw is look at the blade where it cuts the line. I don't line up the notch at the front of the saw plate with the line on the board. You'll notice that it is easier to see the line on the board when the blade is cutting to the left of the line. This isn't always possible, especially cutting out stringers. Just cut slowly through the stringer. If you see the blade wandering off the line, pull the saw back a bit and correct it.

When you come to where the lines on the stringer intersect at a 90 degree angle, stop cutting. Don't cut past the line. After cutting all the lines with your circular saw, go back and finish the cuts (straight down) with a hand saw, jig saw or reciprocating saw. On a stringer you want to leave as much wood under the treads as possible so don't cut any strands of grain that don't have to be cut.

Question about riser on top of or under tread:

When installing stair treads and risers some people are telling us the riser goes on top of the tread. We prefer the look of it behind the tread and thats what it looks like on your page. We just want to know the correct way of installing the riser.


As with any job, there is more than one way of doing it. Regarding the riser behind the tread question, I agree with you. It looks better first of all, but more important is the fact that the riser actually helps support the next higher tread. The riser goes behind the lower tread and is nailed to it and fits under the upper tread supporting it as well. The risers are nailed onto the stringer first, then the treads nailed on after.

Start at the bottom riser, narrower than others, then put on the next riser up. Now nail the first tread on the stringers and nail the riser onto the tread. Use glue to prevent squeaks. Work your way up the set of steps this way.

Question about attaching stringer to floor joist:

What is the best way to attach the stringers to the floor joist?


Some carpenters attach a top riser to the two stringers, then lift them both up and attach the riser to the floor joist. The riser in this case would be 3/4" plywood screwed securely into the upright part of the stringers and into the floor joists. Allow for this thickness when cutting the end of the stringer.

What I prefer to do is attach the stringer to the floor joist with toe nails (from the side of the stringer into the floor joist). Then place posts under the stringer, every 4-5 feet. This also eliminates any spring in the stringers. Don't rely on nails alone holding the stringer. If posts under the stringer would look unsightly, say on an outside stair from a deck, I try to use 4x4 posts for the handrail to support the stringer (from a pad on the ground up to under the rail) a couple of carriage bolts at each intersection would do the trick there.

Question about unusual rise/run sizes:

I'm wanting to build some stairs and I want the total rise to be 2 1/2 feet high, the rise 6 inches and the run 12 inches. Can you give a diagram of what it will look like?


We use the handy stair calculator my brother Dan made for us and we get all the numbers we need. Hope this helps, Hand sketch of deck stairs attached to the deck joist of a backyard deck with measurements.

Question about how to build deck stairs:

I just built a new deck, which turned out rather well. I am however having difficulty making up steps. My total rise from the ground to the top of the deck board is 20.5". I imagine I will need three risers of 6 27/32 inches. I will be using 5/4 x 6 deck boards for the treads and the backs will be open. The two boards for my tread will turn out to be 11". I guess they should overhang a bit. I would like my steps to be 48" across.


Remember that for 3 risers there are 2 treads. A carpenter never makes a set of stairs with the same number of treads as risers. If he did, the top tread would be flush with the upper floor or deck. Always place that first step down one riser from the floor or deck surface.

I would make the run 10 3/4" to give about a 1/2" overhang with about 1/4" gap between the boards. You've got the rise correctly figured as 6 27/32". I would recommend that you use pressure treated wood for the stringers, supports and pads. Also for 48" wide stairs, 3 stringers are required. Be sure to compact the dirt well under the pads. Hand drawn sketch of stringer details showing front and side views with measurements.

Question about attaching top rail to newel posts:

I am installing a handrail on my landing and down the stairs. Your instructions given on how to do this includes everything I need except how to attach the handrail to the newel posts. Could you explain how to do that?


This is what I wrote in the article to fasten the top rail to the newel post: Put the whole assembly into position, pre-drill for wood screws from the top rail into the newel on the angle, use glue on all joints. There are small headed, hard screws available for this purpose at the finishing store.

Photo of the details of how the top rail of a balustrade joins the newel post.

Notice the 2 holes filled with putty on the underside of the top rail, in the above picture. This is where the screws are used to attach the 2 pieces. Use the screws as you would a toe-nail - on the angle from the rail into the newel. You should have enough room between the spindle and the newel post. These screws are 3" long with a very small head and are very hard for screwing into oak or other hardwoods. A standard 3" x # 10 flat head wood screw would work, but the head is larger and you would have to pre-drill into the newel. Make sure the end of the rail is completely covered with Carpenter's Yellow glue, then wipe the excess off with a damp rag after tightening the screws.

When going down the stairs, the top rail is installed first, before the spindles. The lower newel and rail are attached as described above. The upper newel and top rail are attached from the face of the top rail into the newel. Unfortunately, this leaves a hole that needs to be plugged rather than puttied, since it is in full view. Usually, a 3/8" hardwood plug is used to fill a 3/8" hole in the rail, as shown in this picture, below.

Photo of the top of a newel post.

I would recommend buying a 3/8" plug cutter, an inexpensive tool. This way you can make your own plugs out of scraps of the particular hardwood you are using for instances such as this.

Question about how to stabilize stringers:

I have straight-run, open-riser stairs (brick wall on one side and open on the other) up two stories. Each flight has about 17 risers. I was planning on using 2x12s for the stringers, but once they were installed (on 3/4" hanger board at top) and the treads were put on, they were still very "bouncy" (they kind of sway - we can push them back and forth) in the center (and kind of scary). Will this "bounce" subside when the railings are installed, or is there some part that we are missing?


You should put a 2x4 post under the stringer to take this bounce away. Also try to tie the stringer into the brick wall to take out the sway. The railings won't stiffen up the stringers unless they were solid or built like a truss.

Question about splicing long stringers:

I need to make Stringers for a 10' rise. This will work out to the stringer being 18 to 20 feet long. I can only find 16' 2 X 12's. Is it okay to splice them to make them long enough? if so HOW?


Most building supply yards that deal with contractors sell dimension lumber to 20'. Home Depot®, etc. only sell popular lengths to 16'.

You can build a set of stairs to a maximum total rise of 12' according to the code. You need a stringer of about 18', so I would get a stringer of 10' and 8' and splice them together with a 4' slice: 2' on each side of the joint, using a 2x12 as the splice. Put the splice on one side only and layout the opposite side. Just tack the splice in place until it is laid out. Then you can cut out the stringer and splice together. Then screw or nail the splice together well.

You should support the stringer with posts to take the bounce out, as mentioned in my stair articles.

Question about veneering an existing skirt board:

I need to put new treads and risers on my indoor entry stairs. How do I remove the existing skirt boards? Or do I just veneer the old ones?


Some times the skirt board is installed attached to the stringer, so it may not be easy to remove. Regardless, I would keep the skirt there and veneer it with about 1/8" or 1/4" plywood and add a solid wood cap. Do this first, before adding the new risers and treads. The skirt is not the easiest thing to veneer, so it is easier to cut the risers and treads tight to the skirt than vice versa.

Make a pattern from cardboard. Cut these strips a bit wider than the skirt board to allow for scribing against the existing tread and riser. Once you are happy with the fit, trim the veneer off flush with the top of the skirt board and finish it with a piece of oak, or whatever choice of wood, running on the top of the skirt, acting as a cap to cover the end grain of the veneer and top edge of the old skirt. Then fit the new treads and risers to the skirt. Watch the height of the risers. You don't want to change these too much - your risers should be consistent in height from floor to floor.

Question about standard size of stringer:

Dave what's the standard size board for a stringer?


The standard board used for a stringer is either 2x10 or 2x12. The requiring factor is that after the stringer is cut it should have 3 1/2" left below the notches for strength.

Question about width of stairs:

What width should indoor stairs be? They will be going to a master bedroom upstairs. I was thinking about 42". They will be a straight run.


Yes, 42" is a good width of stairs. The minimum, as suggested by the building code, is 36" above the handrails to the finished drywall, etc.


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Your source for building tips, woodworking & furniture plans, house plans and building advice directly from Dave...

Hi, I'm Dave Osborne. With over 50 years experience as a journeyman carpenter, foreman and contractor in heavy construction I enjoyed working with apprentices and sharing the tricks of the trade that others shared with me. Now I get emails from Members all over the world and we include many of my answers in our Free Monthly Newsletters. Some of my answers include drawings and instructions specific to a project, but may also answer your questions. I use correct construction terminology, so you can confidently inform your building supply dealers or contractors exactly what you need.


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